Core B provides technical support for all projects. It includes three parts: (1) Protein Chemistry: provides amino acid composition and sequence analyses, and synthesis of peptides using various state-of-the-art facilities. It will also offer advice to individual PI's on peptide/fragment purification and characterization. This service will be used essentially by every project, with less emphasis in Projects II-C and III. (2) Analytical Ultracentrifugation: provides both sedimentation velocity and sedimentation equilibrium runs, as well as related hydrodynamic analyses; it will support Projects I-A, I-B, II-A and II-B. (3) Electron Microscopy and Immunocytochemistry: provides technical expertise and advice for the EM visualization of proteins, especially with an improved rotary shadowing technique recently developed by one of the PI's, and supports the preparation of polyclonal and monoclonal antibodies, including the handling of laboratory animals. This service will be needed in Projects I-A, II-A, II-B and possibly I-B and III.